Rheological Properties and Physical Stability of O/W Emulsions Stabilized by Diacylglycerols Formed During Enzymatic Interesterification

The purpose of this work was evaluation of stability of emulsions containing modified fats obtained by enzymatic interesterification of mutton tallow with walnut oil, determination of the optimal range of thickener content, and preferable processing conditions. Modified fats were produced by enzymatic interesterification of mutton tallow with walnut oil. It has been shown that by intentional forcing of hydrolysis process by addition 13 wt% of water into reaction mixture the highest amount of polar fraction in the final product was observed. The physicochemical parameters of the obtained fats were determined in this study. To reveal the stability of the investigated emulsions the comprehensive tests with Turbiscan enabling detailed investigation of the droplet size distribution, dispersion index, morphology, and microstructure were performed. Additionally, to get a full picture of the emulsions stability the rheological measurements in oscillatory mode were carried out. Taking into consideration the physicochemical properties of the investigated emulsions it was found that emulsions containing carboxymethylcellulose exhibited the highest stability. The emulsifiers formed during enzymatic interesterification allow formation of a stable emulsion system. This offers the unique opportunity of using interesterified fat as the oil phase in preparation of emulsions for food, cosmetic and pharmaceutical industries